Understanding the indirect land use change analysis for CORSIA

This new report looks in detail at the assumptions and criteria used to determine the "indirect land use change" of biofuels under the UN's carbon offsets scheme for aviation emissions (known as Corsia). The report, commissioned by T&E from consultancy Cerulogy, reveals several biases in the choice of some crucial modelling assumptions and in the decision on the final ILUC numbers. Corsia, the Carbon Offsetting and Reduction Scheme for International Aviation adopted by ICAO, includes the option for airlines to meet their emission reduction obligations by using alternative aviation fuels that are calculated to have a lower greenhouse gas emissions footprint than the fossil jet fuel they replace. The calculation of indirect land use change (ILUC) emissions is part of this assessment and the US and EU delegations supported ILUC modelling using two different analytical frameworks, the ‘GTAP-BIO’ and ‘GLOBIOM’ models. ILUC factor results from these modelling exercises have become the basis for the default values proposed for CORSIA.